锯缘青蟹窦腺显微和超微结构研究

借助光学和电子显微镜观察据缘青蟹（Ｓｃｙｌｌａ ｓｅｒｒａｔａ）窦腺的形态结构。窦腺位于眼柄视神经节内髓背侧近外髓处。窦腺呈羹状;腺体壁山神经分泌细胞的末梢和神经胶质细胞组成。神经末梢内充满了电子致密的神经分泌颗粒。根据颗粒的大小、形态及电子致密度等特征,可以区分出４种类型的神经末梢。一些末梢中的多形性颗粒可能是由Ⅱ型末梢中的颗粒转变而成的。一些现象表明,神经分泌物质可以通过胞吐作用或一种类似“顶浆分泌”的方式释放,从而说明神经激素的释放可能是多途径的．     

中华绒螯蟹窦腺神经末梢及X-器官神经分泌细胞的类型

在电子显微镜下观察了性未成熟的中华绒螯蟹黄蟹的窦腺及X－器官的超微结构。X－器官位于眼柄神经节终髓的腹外侧,与窦腺位置斜相对,窦腺主要由神经分泌细胞的末梢和胶质细胞组成。神经末梢含有大量的膜结构包围的颗粒、线粒体、粗面内质网和许多电子透明的小泡,末梢外周有时可见指状突起。依据颗粒的大小、形状、电子致密度以及胞质特征,可区分出6种类型的窦腺神经末梢及7种X－器官神经分泌细胞。观察了末梢中神经分泌颗粒的胞吐作用方式的释放过程,并且尝试对窦腺不同末梢中的颗粒及X－器官神经分泌细胞中的颗粒作了比较,发现二者之间具有较好的对应性,即电子致密度无大的变化,形态特征相似,只是大小稍有增加。     

河蟹眼柄神经分泌细胞离子通道的膜片钳研究

采用全细胞膜片钳技术对培养12－24小时不同形态河蟹眼柄视节端髓X器官（MTXO）神经分泌细胞离子通道进行了研究。结果表明,河蟹眼柄MTXO中分布的A、B、C三种类型神经分泌细胞均可记录到由向电流和外向电流组成的正常全细胞电流。内向电流由高电压激活钙离子通道电流（Lca)和对TTX敏感钠离子通道电流（INa）组成。ICa的激活电压为－30mV,在0－ 20mV电压下达到峰值,在－40mV和－70mV保持电压下记录的ICa激活阈值、初始峰值及I－V曲线无明显差别。外向电流明显,幅值较大,包括对4－AP敏感的快速激活、快速失活钾离子通道电流（IA）和对TEA敏感的缓慢激活、缓慢失活钾离子通道电流（IK）。正常蟹种、二龄成蟹和早熟蟹种MTXO神经分泌细胞均表达电压门控钠、钾、钙离子通道,通道电流和电压特征无明显区别.     

中华绒螯蟹胸神经团神经分泌细胞的显微和超显微结构观察

应用光学显微镜和电子显微镜技术,研究了中华绒螯蟹(Eriocheir sinensis)胸神经团的神经分泌细胞,描述了其显微和超显微结构。依据细胞形态、细胞核、内分泌颗粒和细胞质的特征将胸神经团神经分泌细胞分为3种类型:Ⅰ型细胞最大,胞质中存在许多大小不同的空泡,分泌颗粒数量很少;Ⅱ型细胞中等大小,细胞器发达,分泌颗粒数量较多,形态多样;Ⅲ型细胞最小,分泌颗粒数量最多,细胞器很少。     

北京鸭产卵期输卵管管状腺细胞超微结构研究

用电子显徽镜对北京鸭输卵管管状腺细胞进行观察。鸭输卵管由五部分组成:漏斗、蛋白分泌部、峡部、壳腺和阴道。蛋白分泌部的管状腺细胞有四种类型。A型细胞有电子密度深色颗粒;B型细胞充满了无定型低电子密度物质;C型细胞具有非常明显的粗面内质网和高尔基复合体;D型细胞是由致密的颗粒和低电子密度的颗粒所组成,腔内充满分泌颗粒。我们在这篇文章中分析了蛋白分泌周期的四个不同阶段。     

问题解答

问神经激素与神经递质有什么不同? 答神经激素和神经递质都是细胞之间的化学信息分子。神经激素是神经分泌细胞的核周体产生的活性物质,沿着轴突输送至球状末梢,然后释放到血液中再作用于其靶细胞。神经递质是由神经细胞轴突末梢释放的化学物质,在二个神经元隔开的小间隙(突触)中扩散,或在神经元与效应器细胞间扩散。二者比较如下。     

成年哺乳动物海马中的星形胶质细胞可生成新的神经元

在许多脊椎动物 ,包括人的一生中 ,大脑海马齿状回都会不断生成新的神经元。这些新神经元的前体存在于海马齿状回的亚颗粒层。过去从对成年哺乳动物海马组织的培养中发现 ,干细胞能自我更新并且能生成新的神经元和神经胶质细胞 ,但它们的原始前体细胞尚不清楚 ,研究发现亚颗粒层细胞———一种具有胶质纤维酸性蛋白 (ＧＦＡＰ)免疫标记的星形胶质细胞 ,在正常情况下或在用化学方法去除活跃的分裂细胞之后 ,可分裂和生成新的神经元。我们也对一定数量小的电子致密亚颗粒层细胞 (称之为Ｄ细胞 )进行了研究 ,发现它们起源于星形胶质细胞 ,在新…     

大白鼠第三脑室室管膜的超微结构

本文用扫描和透射电镜证实在成年大白鼠的第三脑室存在室管膜上神经元样细胞、神经胶质细胞和类组织细胞。神经纤维发自神经元样细胞或自脑室外穿入室腔而来,其末梢内含有清亮囊泡或兼有大颗粒囊泡。室腔內尚有膨大的树突末梢和室管膜细胞的球状小体。上述各种结构与感受、分泌和调节功能有关,并为下丘脑控制垂体机能的另一新途径(经脑脊液和室管膜)提供了形态学依据。     

日本血吸虫尾蚴头腺及钻腺的超微结构

通过电镜观察发现：日本血吸虫尾蚴的头腺为多导管的单细胞腺,由腺体部和若干突起状的短导管构成,其分泌小体呈圆形或卵圆形,平均大小为 ０． ２９ × ０． ２３μｍ,具有同心的环层膜状结构。前钻腺含有 Ａ、Ｂ两型分泌小体。 Ａ型分泌小体近似圆形,平均大小为 ０． ４６× ０． ３２μｍ,基质为电子致密的均 匀结构;Ｂ型分泌小体数量众多,略呈不规则的圆形,平均大小为１．０２×０．８２μｍ,基质为中等电子致 密并含十余个小圆形的电子透亮区。后钻腺含有椭圆形或长条状的分泌小体,平均大小为０．９７×０．６２μｍ,基质呈同质性,或伴有电子密度较深的圆形聚集物,或基质呈泡沫状。每根钻腺导管 的胞质外周具有许多沿导管长轴纵行的微管结构,在导管周围有纤维性网状构造包绕,起着对细长导管的支架作用。在导管束外周又有大量肌纤维包统而形成的鞘状结构,它对管内分泌小体的排出可能具有选择性控制作用。     

麝鼠香腺发育及腺细胞培养分离的初步研究

目前麝鼠香是麝香最好的天然替代物,麝鼠香来源于麝鼠生殖系统中的香腺,已发现其香腺中分泌细胞和支持细胞是麝鼠泌香的关键。本研究通过组织形态、HE染色、免疫组织化学染色及免疫荧光鉴定方法,初步描述了麝鼠香腺的发育过程。麝鼠香腺的形态结构显示其由小到大再至非泌香期萎缩;HE染色及组化结果显示,香腺在发育初期富含颗粒饱满的腺泡,雄激素分泌处于较低水平,分泌细胞数量较少,随着进一步发育,雄激素水平及分泌细胞数量逐渐升高,在两个月时达到最高,腺泡逐渐变大成熟并开始释放麝鼠香等分泌物;在泌香末期,腺泡逐渐被结缔组织取代。以上结果将有助于麝鼠香腺发育及分泌机制的研究,为提高麝香产量及实现体外泌香建立基础。另外,我们成功分离并鉴定了分泌细胞和支持细胞,以期为后续建立体外泌香体系奠定基础。     

Autolysis in axon terminals of a new neurohaemal organ in the cockroach Periplaneta americana

An ultrastructural investigation showed that there was a neurohaemal organ in the wall of the ampulla of the antennal pulsatile organ. The neurosecretory axon terminals occurred singly or in small groups rather than closely packed together as in other neurohaemal organs. All axons contained the same type of neurosecretory granule. The granules had varying electron density and a diameter in the range 1000–2500 Å. Some terminals contained small, elliptical, electron-transparent vesicles and the axolemma was apposed to the stroma. Other terminals were large and enveloped by glial tissue and the contents of the terminals exhibited varying degrees of autolytic degeneration. Autolysis was characterized by the occurrence of dense bodies and multilaminate bodies which enclosed mitochondria and neurosecretory granules. It was suggested that the neurosecretory material affects antennal function.     

Neurosecretory centers from the eyestalk of Siriella armata M. Edw. (Crustacea: Mysidacea): ultrastructural variations during normal and experimentally inhibited molt cycle

Summary The ultrastructure of the medulla interna-medulla externa X-organ (MI-ME Xo)-sinus gland (SG) complex in the eyestalk of Siriella armata is described during the normal and the experimentally inhibited molt cycle. In the normal SG, four types of neurosecretory axon terminals, each containing distinguishable neurosecretory granules, can be described. Thus, type-2 granules are synthesized by G1 neurons forming the MI-ME Xo. The cell bodies and axonal endings of these cells in the sinus gland have been examined at the following molt stages: intermolt (stage C4), premolt (D0 and D2), and postmolt (A1, A2 and B). Changes in ultrastructure of the G1 cells have been monitored and correlated to inhibitions of the molt-and reproductive cycle produced by electrocauterization of the MI-ME Xo. The results obtained suggest that the neurosecretion from the G1 cells exerts a positive influence on molt and brood preparation. The occurrence of a distal group of G1 cells whose axons terminate at a different site from the SG suggests that the neural factors of the MI-ME Xo are diverse and control different physiological activities.     

Localization of crustacean hyperglycemic hormone (CHH) in the X-Organ sinus gland complex in the eyestalk of the crayfish,Astacus leptodactylus (Nordmann, 1842)

The eyestalk of Astacus leptodactylus is investigated immunocytochemically by light, fluorescence, and electron microscopy, using an antiserum raised against purified crustacean hyperglycemic hormone (CHH). CHH can be visualized in a group of neurosecretory perikarya on the medualla terminalis (medulla terminalis ganglionic X-organ: MTGX), in fibers forming part of the MTGX-sinus gland tractus, and in a considerable part of the axon terminals composing the sinus gland. Immunocytochemical combined with ultrastructural investigations led to the identification of the CHH-producing cells and the CHH-containing neurosecretory granule type.     

放养河蟹对黑龙江东湖水库底栖动物和水生维管束植物的影响

在面积为2700hm2的东湖水库,以散养的方式养殖河蟹。在放养密度不同的情况下,研究放养河蟹对水库中底栖动物和水生植物的影响。2001年规格为220只/kg河蟹放养量为1500kg、密度为122只/hm2时,对摇蚊幼虫和寡毛类影响显著,而对其他软体动物和水生植物无显著影响。2002年同样规格的河蟹放养量增加至3500kg、密度为285只/hm2时,对底栖动物和部分沉水植物影响显著。本文对河蟹养殖容量作了讨论,认为东湖水库散养河蟹的放养量不应超过1500kg。     

Neurosecretion in the sinus gland of the fiddler crab,Uca pugnax

The ultrastructure of the sinus gland of the fiddler crab, Uca pugnax, was investigated and found to be similar to that in other crustaceans. Five types of neurosecretory axon terminals were tentatively identified on the basis of the size, shape, and electron density of granules within the axons. Release of neuro-secretory material appears to be by exocytosis.     

Fine structure of the neurohemal sinus gland of the shore crab,Carcinus maenas,and immuno-electron-microscopic identification of neurosecretory endings according to their neuropeptide contents

Summary The sinus gland of the shore crab, Carcinus maenas, is a compact assembly of interdigitating neurosecretory axon endings abutting upon the thin basal lamina of a central hemolymph lacuna. Four types of axon endings are distinguishable by the size distribution, shape, electron density and core structure of their neurosecretory granules. One additional type of axon ending is characterized by electron-lucent vacuoles and vesicles. The axon profiles are surrounded by astrocyte-like glial cells. Various fixations followed by epoxy- or Lowicrylembedding were compared in order to optimize the preservation of the fine structure of the granule types and the antigenicity of their peptide hormone contents. By use of specific rabbit antisera, the crustacean hyperglycemic, molt-inhibiting, pigment-dispersing, and red-pigment-concentrating hormones were assigned to the four distinct granule types which showed no overlap of immunostaining. Epi-polarization microscopy and ultrathin section analysis of immunogold-stained Lowicrylembedded specimens revealed that immunoreactivity to Leu-enkephalin and proctolin is co-localized with moltinhibiting hormone immunoreactivity in the same type of granule. The size and core structure of the immunocytochemically identified granule types vary little with the different pretreatments but, in some cases, to a statistically significant extent. The present results are compared with those from earlier studies of sinus glands in different crustaceans. The methods of granule identification used in this study supplement the classical approach in granule typing; they are easier to perform and more reliable for the analysis of release phenomena in identified secretory neurons supplying the neurohemal sinus gland.     

Immunogold labelling of serotonin-like and FMRFamide-like immunoreactive material in neurohaemal areas on abdominal nerves of Rhodnius prolixus

The ultrastructure of neurohaemal areas on abdominal nerves of the blood-sucking bug Rhodnius prolixus was investigated. Four types of axon terminals were found, distinguished by the morphology of their neurosecretory granules. By use of post-embedding immunogold labelling, granules in Type I axon terminals were shown to contain serotonin-like immunoreactive material, and granules in Type II axon terminals were shown to contain FMRFamide-like immunoreactive material. There was no colocalization of these materials. It is suggested that Type III terminals contain peptidergic diuretic hormone, which has previously been reported to be present in electron-dense neurosecretory granules in this neurohaemal area. The identity of material in Type IV terminals is unknown.     

Invasion biology of the Chinese mitten crab Eriochier sinensis: A brief review

The Chinese mitten crab Eriocheir sinensis is a native of freshwater and estuarine habitats along the east coast of Asia. Invasive populations have existed in northern Europe since the early 20th century, and more recently a breeding population has become established in the San Francisco Bay system along the west coast of North America. Ballast water is the most probable vector for both invasions, although there is also potential for escape from ethnic markets and from the ornamental aquarium industry. Invasive populations of mitten crabs have caused millions of dollars in economic and ecological damage. Economic impacts center largely on the burrowing activity of the crabs, which damages stream banks and levees, and the annual spawning migration, which interferes with fishing activities and irrigation projects. Chinese mitten crabs have recently appeared in the Chesapeake and Delaware Bays on the east coast of the USA, and there are confirmed reports of breeding females in both estuaries. The potential for large populations of mitten crabs in these estuaries has not been determined. This paper presents a review of the biology and ecology of native and invasive populations of the species and provides recommendations for research relevant to the prediction of future mitten crab invasions.